The nation’s ambassador to the United States, Jose Goni, listed Chile’s top priorities Monday afternoon.

“After a detailed assessment of the situation,” Goni said, “the Chilean government has requested aid from the U.S. government consisting essentially of field hospitals, power generators, water-purification plants, rescue teams, medical crews, tents, satellite telephones, temporary infrastructure for people in need and dialysis autonomous systems.”

[ . . . ]

U.S. Secretary of State Hillary Clinton traveled to Santiago for a brief visit Tuesday on a previously scheduled trip through Latin America. She had originally been scheduled to arrive Monday.

Clinton brought with her 20 satellite phones and a technician, part of the aid the United States will provide to Chile.

Chilean Foreign Minister Mariano Fernandez ticked through a list of promised international aid: from Canada, 150 portable houses; China, $1 million and a field hospital; South Korea, a planeload of medical equipment; Cuba, a portable hospital equipped with a surgical suite and 25 doctors; Indonesia, $1 million; the European Union, $4 million; Spain, rescue teams, including structural engineers and search dogs; Japan, $3 million and emergency materials; the United Nations, health aid.

Other promised aid, according to Fernandez: from Argentina, three portable hospitals; Peru, one portable hospital and 25 doctors; France, a team of 15 structural engineers; the Organization of American States, 20 satellite phones; the United States, 60 satellite phones; Switzerland, a team of engineers; Russia, 100 portable houses and seven tons of food; Uruguay, two water-purification plants.

[ . . . ]

Bachelet said all emergency measures should be in place by Tuesday.

Carmen Fernandez, director of the National Emergency Office, said Tuesday afternoon that aid is starting to reach all regions. Distribution is becoming standardized, she said, and the flow of aid is starting to become constant.

Rescuers in the hardest-hit areas, including Concepcion and the Maule and Bio Bio regions, continued to scramble to reach possible survivors Tuesday.

At least 12 aftershocks were recorded in the past 24 hours, ranging in magnitude from 4.8 to 5.3, the U.S. Geological Survey reported. The strongest of the more than 90 aftershocks was a 6.2-magnitude quake on Sunday near the main quake’s epicenter.

Although damage was significant in Santiago, the nation’s capital, electricity and water were restored to much of the city by late Monday and many residents could use their cell phones and other conveniences. About 90 percent of the city’s stores were open.

[ . . . ]

But some of that aid was temporarily delayed Tuesday at a military checkpoint on the Itata Route about 12 miles (20 kilometers) outside of Concepcion. Images broadcast by CNN Chile showed at least 12 tractor-trailers filled with aid stopped at the checkpoint. Dozens of other vehicles were lined up, stretching to the horizon, behind the trucks.

One truck driver said he had been waiting for four hours.

An unidentified army captain interviewed at the checkpoint said if it was up to him the convoy would pass, but he had to wait for approval from the National Emergency Office.

[ . . . ]

The threat of violence slowed the flow of aid, said Michael Black of the nongovernmental organization World Vision. “The truth is it’s taken a lot longer than needed for them to deploy the forces and re-establish order, which is necessary for any NGO,” he told CNN.

The Christian humanitarian group had not yet released any supplies from its warehouse in Santiago, he said. He predicted that would change on Wednesday.

[etc.]

The death toll from Saturday’s 8.8-magnitude earthquake in Chile reached 795 on Tuesday, the president’s office said.

Officials say the tally likely will increase in coming days as search-and-rescue crews dig into collapsed buildings and discover more bodies.

Bachelet said Saturday that about 2 million people had been affected in some way, but she did not elaborate. The Chilean Red Cross reported that about 500,000 homes had considerable damage.

The armed forces were available to help with security and the distribution of food, she said.

Death toll at 795 in Chile quake, government says

Clinton promises solidarity, supplies for quake-damaged Chile

Santiago, Chile (CNN) — U.S. Secretary of State Hillary Clinton arrived Tuesday morning in Chile, bringing with her more than two dozen satellite phones and a pledge of U.S. commitment to the earthquake-damaged nation.

[ . . . ]

The secretary of state said she brought with her 25 satellite phones, one of which she presented to Bachelet at the news conference. Eight water purification units are on their way to Chile, Clinton said, and the United States will provide a mobile field hospital unit with surgical capabilities.

The United States will also work to provide autonomous dialysis machines, electricity generators, medical supplies and portable bridges, Clinton said.

The secretary of state also said that Americans would be told how they can contribute to the recovery effort.

In addition to meeting with Bachelet at the airport in Santiago, Clinton also met with President-elect Sebastian Piñera, who will be sworn in next week.

“I have been visiting sites of disaster for more than 30 years … [and] it is very clear to me that Chile is much better prepared, much quicker to respond, more able to do so,” Clinton said at a news conference with the president-elect.

Latest Earthquakes Magnitude 5.0 and Greater in the World – Last 7 days

Magnitude 5 and greater earthquakes located by the USGS and contributing networks in the last week (168 hours). Magnitudes 6 and above are in red. (Some early events may be obscured by later ones on the maps.)

LISS home page. The Live Internet Seismic Server (LISS) brings in live seismic data, via the Internet, from seismographic stations around the world. This page provides links to live seismic data, current telemetry status and general and detailed information on the LISS. For those interested in connecting directly to the LISS and receiving live (raw) data directly to their computer, see the connection notes…

In Chile, an 8.8-magnitude earthquake on Saturday has so far killed more than 700 people. On January 12, a less powerful earthquake, one measuring 7.0, killed more than 200,000 in Haiti.

The difference in those death tolls comes from building construction and technology, scientists and engineers have said. In Haiti, buildings were constructed quickly and cheaply. Chile, a richer and more industrialized nation, adheres to more stringent building codes.

[ . . . ]

Technology designed to keep buildings from collapsing works essentially in two ways: By making buildings stronger, or by making them more flexible, so they sway and slide above the shaking ground rather than crumbling.

In search of an earthquake-proof building

It would be a start for more developing countries to adopt building codes that include measures about earthquake resistance, he said, but that wouldn’t fix everything.

Armstrong said people all over the world, and with all job types, from city planners to construction workers, need to be aware of technologies and building methods that prevent buildings from collapsing in earthquakes.

“You can write a really good code, but you’d better have the capacity to enforce it,” he said. “You’ve got to have people on the ground who are trained and certified in codes and are willing to enforce the codes.”

[ . . . ]

“Most disasters are created by human beings. It’s how we build and where we build that creates the hazard, the disaster,” said Michael Armstrong, senior vice president of the International Code Council, a nonprofit group that develops building codes for countries to adopt. “Earthquakes, hurricanes, fires, floods are going to occur, but there are ways in terms of where we build and how we build that can reduce the impact.”

[etc.]

New buildings with earthquake-resistant technology cost about 5 to 10 percent more than those built without the precautions, engineers said.

The cost of retrofitting old buildings to modern earthquake standards is much more expensive but has been tried in certain cases, such as when the city of San Francisco retrofitted its city hall with base-isolation technology.

[ . . . ]

Mehmet Celebi, a senior research civil engineer at the U.S. Geological Survey, said there have been striking examples where buildings made with base isolation survived earthquakes while others did not. He said a University of Southern California hospital in Los Angeles, for example, survived a 1994 earthquake “absolutely unharmed.”

A neighboring hospital building that did not use the isolation technology suffered considerable damage, he said.

[ . . . ]

For about 30 years, engineers have constructed skyscrapers that float on systems of ball bearings, springs and padded cylinders. They don’t sit directly on the ground, so they’re protected from some earthquake shocks. In the event of a major earthquake, they sway up to a few feet. The buildings are surrounded by “moats,” or buffer zones, so they don’t swing into other structures.

“You actually take the foundation of building and you put it either on almost like springs or on a mechanism so it is allowed to move a little bit with the earthquake,” said Armstrong of the building code council.

Well-designed buildings with base-isolation systems ensure that no lives will be lost, no matter the strength of an earthquake, said Michael Constantinou, a professor of civil engineering at the University at Buffalo, State University of New York.

But can people engineer buildings that wouldn’t crumble when subjected to the rumblings of the Earth?

In the wake of the Haiti and Chile earthquakes, such a question has more importance now than any time in recent memory.

The simple answer is yes. The technology exists to make buildings nearly earthquake-proof today. However, installing those safer buildings all over the world isn’t so simple. Neither is figuring out who will pay.

In a handful of interviews, engineers who work on earthquake-resistant buildings said current technologies prevent well-designed buildings from cracking when the ground shakes beneath them.

(creatively excerpted from -)

Many buildings in Chile withstood a stronger earthquake than one in Haiti, which toppled concrete structures.

World Book at NASA

Earthquake

Earthquake is a shaking of the ground caused by the sudden breaking and shifting of large sections of Earth’s rocky outer shell. Earthquakes are among the most powerful events on earth, and their results can be terrifying. A severe earthquake may release energy 10,000 times as great as that of the first atomic bomb. Rock movements during an earthquake can make rivers change their course. Earthquakes can trigger landslides that cause great damage and loss of life. Large earthquakes beneath the ocean can create a series of huge, destructive waves called tsunamis (tsoo NAH meez)that flood coasts for many miles.

Earthquakes almost never kill people directly. Instead, many deaths and injuries result from falling objects and the collapse of buildings, bridges, and other structures. Fire resulting from broken gas or power lines is another major danger during a quake. Spills of hazardous chemicals are also a concern during an earthquake.

The force of an earthquake depends on how much rock breaks and how far it shifts. Powerful earthquakes can shake firm ground violently for great distances. During minor earthquakes, the vibration may be no greater than the vibration caused by a passing truck.

On average, a powerful earthquake occurs less than once every two years. At least 40 moderate earthquakes cause damage somewhere in the world each year. Scientists estimate that more than 8,000 minor earthquakes occur each day without causing any damage. Of those, only about 1,100 are strong enough to be felt.

Most earthquakes occur along a fault — a fracture in Earth’s rocky outer shell where sections of rock repeatedly slide past each other. Faults occur in weak areas of Earth’s rock. Most faults lie beneath the surface of Earth, but some, like the San Andreas Fault in California, are visible on the surface. Stresses in Earth cause large blocks of rock along a fault to strain, or bend. When the stress on the rock becomes great enough, the rock breaks and snaps into a new position, causing the shaking of an earthquake.

Earthquakes usually begin deep in the ground. The point in Earth where the rocks first break is called the focus, also known as the hypocenter, of the quake. The focus of most earthquakes lies less than 45 miles (72 kilometers) beneath the surface, though the deepest known focuses have been nearly 450 miles (700 kilometers) below the surface. The point on the surface of Earth directly above the focus is known as the epicenter of the quake. The strongest shaking is usually felt near the epicenter.

From the focus, the break travels like a spreading crack along the fault. The speed at which the fracture spreads depends on the type of rock. It may average about 2 miles (3.2 kilometers) per second in granite or other strong rock. At that rate, a fracture may spread more than 350 miles (560 kilometers) in one direction in less than three minutes. As the fracture extends along the fault, blocks of rock on one side of the fault may drop down below the rock on the other side, move up and over the other side, or slide forward past the other.

How an earthquake spreads

When an earthquake occurs, the violent breaking of rock releases energy that travels through Earth in the form of vibrations called seismic waves. Seismic waves move out from the focus of an earthquake in all directions. As the waves travel away from the focus, they grow gradually weaker. For this reason, the ground generally shakes less farther away from the focus.

There are two chief kinds of seismic waves: (1) body waves and (2) surface waves. Body waves, the fastest seismic waves, move through Earth. Slower surface waves travel along the surface of Earth.

Body waves tend to cause the most earthquake damage. There are two kinds of body waves: (1) compressional waves and (2) shear waves. As the waves pass through Earth, they cause particles of rock to move in different ways. Compressional waves push and pull the rock. They cause buildings and other structures to contract and expand. Shear waves make rocks move from side to side, and buildings shake. Compressional waves can travel through solids, liquids, or gases, but shear waves can pass only through solids.

Compressional waves are the fastest seismic waves, and they arrive first at a distant point. For this reason, compressional waves are also called primary (P) waves. Shear waves, which travel slower and arrive later, are called secondary (S) waves.

Body waves travel faster deep within Earth than near the surface. For example, at depths of less than 16 miles (25 kilometers), compressional waves travel at about 4.2 miles (6.8 kilometers) per second, and shear waves travel at 2.4 miles (3.8 kilometers) per second. At a depth of 620 miles (1,000 kilometers), the waves travel more than 11/2 times that speed.

Surface waves are long, slow waves. They produce what people feel as slow rocking sensations and cause little or no damage to buildings.

There are two kinds of surface waves: (1) Love waves and (2) Rayleigh waves. Love waves travel through Earth’s surface horizontally and move the ground from side to side. Rayleigh waves make the surface of Earth roll like waves on the ocean. Typical Love waves travel at about 23/4 miles (4.4 kilometers) per second, and Rayleigh waves, the slowest of the seismic waves, move at about 21/4 miles (3.7 kilometers) per second. The two types of waves were named for two British physicists, Augustus E. H. Love and Lord Rayleigh, who mathematically predicted the existence of the waves in 1911 and 1885, respectively.

Damage by earthquakes

How earthquakes cause damage

Earthquakes can damage buildings, bridges, dams, and other structures, as well as many natural features. Near a fault, both the shifting of large blocks of Earth’s crust, called fault slippage, and the shaking of the ground due to seismic waves cause destruction. Away from the fault, shaking produces most of the damage. Undersea earthquakes may cause huge tsunamis that swamp coastal areas. Other hazards during earthquakes include rockfalls, ground settling, and falling trees or tree branches.

Fault slippage

The rock on either side of a fault may shift only slightly during an earthquake or may move several feet or meters. In some cases, only the rock deep in the ground shifts, and no movement occurs at Earth’s surface. In an extremely large earthquake, the ground may suddenly heave 20 feet (6 meters) or more. Any structure that spans a fault may be wrenched apart. The shifting blocks of earth may also loosen the soil and rocks along a slope and trigger a landslide. In addition, fault slippage may break down the banks of rivers, lakes, and other bodies of water, causing flooding.

Ground shaking causes structures to sway from side to side, bounce up and down, and move in other violent ways. Buildings may slide off their foundations, collapse, or be shaken apart.

In areas with soft, wet soils, a process called liquefaction may intensify earthquake damage. Liquefaction occurs when strong ground shaking causes wet soils to behave temporarily like liquids rather than solids. Anything on top of liquefied soil may sink into the soft ground. The liquefied soil may also flow toward lower ground, burying anything in its path.

Tsunamis

An earthquake on the ocean floor can give a tremendous push to surrounding seawater and create one or more large, destructive waves called tsunamis, also known as seismic sea waves. Some people call tsunamis tidal waves, but scientists think the term is misleading because the waves are not caused by the tide. Tsunamis may build to heights of more than 100 feet (30 meters) when they reach shallow water near shore. In the open ocean, tsunamis typically move at speeds of 500 to 600 miles (800 to 970 kilometers) per hour. They can travel great distances while diminishing little in size and can flood coastal areas thousands of miles or kilometers from their source.

Structural hazards

Structures collapse during a quake when they are too weak or rigid to resist strong, rocking forces. In addition, tall buildings may vibrate wildly during an earthquake and knock into each other. Picture San Francisco earthquake of 1906 A major cause of death and property damage in earthquakes is fire. Fires may start if a quake ruptures gas or power lines. The 1906 San Francisco earthquake ranks as one of the worst disasters in United States history because of a fire that raged for three days after the quake.

Other hazards during an earthquake include spills of toxic chemicals and falling objects, such as tree limbs, bricks, and glass. Sewage lines may break, and sewage may seep into water supplies. Drinking of such impure water may cause cholera, typhoid, dysentery, and other serious diseases.

Loss of power, communication, and transportation after an earthquake may hamper rescue teams and ambulances, increasing deaths and injuries. In addition, businesses and government offices may lose records and supplies, slowing recovery from the disaster.

Reducing earthquake damage

In areas where earthquakes are likely, knowing where to build and how to build can help reduce injury, loss of life, and property damage during a quake. Knowing what to do when a quake strikes can also help prevent injuries and deaths.

Where to build

Earth scientists try to identify areas that would likely suffer great damage during an earthquake. They develop maps that show fault zones, flood plains (areas that get flooded), areas subject to landslides or to soil liquefaction, and the sites of past earthquakes. From these maps, land-use planners develop zoning restrictions that can help prevent construction of unsafe structures in earthquake-prone areas.

How to build

An earthquake-resistant building includes such structures as shear walls, a shear core, and cross-bracing. Base isolators act as shock absorbers. A moat allows the building to sway. Image credit: World Book illustration by Doug DeWitt

Engineers have developed a number of ways to build earthquake-resistant structures. Their techniques range from extremely simple to fairly complex. For small- to medium-sized buildings, the simpler reinforcement techniques include bolting buildings to their foundations and providing support walls called shear walls. Shear walls, made of reinforced concrete (concrete with steel rods or bars embedded in it), help strengthen the structure and help resist rocking forces. Shear walls in the center of a building, often around an elevator shaft or stairwell, form what is called a shear core. Walls may also be reinforced with diagonal steel beams in a technique called cross-bracing.

Builders also protect medium-sized buildings with devices that act like shock absorbers between the building and its foundation. These devices, called base isolators, are usually bearings made of alternate layers of steel and an elastic material, such as synthetic rubber. Base isolators absorb some of the sideways motion that would otherwise damage a building.

Skyscrapers need special construction to make them earthquake-resistant. They must be anchored deeply and securely into the ground. They need a reinforced framework with stronger joints than an ordinary skyscraper has. Such a framework makes the skyscraper strong enough and yet flexible enough to withstand an earthquake.

Earthquake-resistant homes, schools, and workplaces have heavy appliances, furniture, and other structures fastened down to prevent them from toppling when the building shakes. Gas and water lines must be specially reinforced with flexible joints to prevent breaking.

Safety precautions are vital during an earthquake. People can protect themselves by standing under a doorframe or crouching under a table or chair until the shaking stops. They should not go outdoors until the shaking has stopped completely. Even then, people should use extreme caution. A large earthquake may be followed by many smaller quakes, called aftershocks. People should stay clear of walls, windows, and damaged structures, which could crash in an aftershock.

People who are outdoors when an earthquake hits should quickly move away from tall trees, steep slopes, buildings, and power lines. If they are near a large body of water, they should move to higher ground. Where and why earthquakes occur

Scientists have developed a theory, called plate tectonics, that explains why most earthquakes occur. According to this theory, Earth’s outer shell consists of about 10 large, rigid plates and about 20 smaller ones. Each plate consists of a section of Earth’s crust and a portion of the mantle, the thick layer of hot rock below the crust. Scientists call this layer of crust and upper mantle the lithosphere. The plates move slowly and continuously on the asthenosphere, a layer of hot, soft rock in the mantle. As the plates move, they collide, move apart, or slide past one another.

The movement of the plates strains the rock at and near plate boundaries and produces zones of faults around these boundaries. Along segments of some faults, the rock becomes locked in place and cannot slide as the plates move. Stress builds up in the rock on both sides of the fault and causes the rock to break and shift in an earthquake.

There are three types of faults: (1) normal faults, (2) reverse faults, and (3) strike-slip faults. In normal and reverse faults, the fracture in the rock slopes downward, and the rock moves up or down along the fracture. In a normal fault, the block of rock on the upper side of the sloping fracture slides down. In a reverse fault, the rock on both sides of the fault is greatly compressed. The compression forces the upper block to slide upward and the lower block to thrust downward. In a strike-slip fault, the fracture extends straight down into the rock, and the blocks of rock along the fault slide past each other horizontally.

Most earthquakes occur in the fault zones at plate boundaries. Such earthquakes are known as interplate earthquakes. Some earthquakes take place within the interior of a plate and are called intraplate earthquakes.

Mid-ocean spreading ridges are places in the deep ocean basins where the plates move apart. As the plates separate, hot lava from Earth’s mantle rises between them. The lava gradually cools, contracts, and cracks, creating faults. Most of these faults are normal faults. Along the faults, blocks of rock break and slide down away from the ridge, producing earthquakes.

Near the spreading ridges, the plates are thin and weak. The rock has not cooled completely, so it is still somewhat flexible. For these reasons, large strains cannot build, and most earthquakes near spreading ridges are shallow and mild or moderate in severity.

Subduction zones are places where two plates collide, and the edge of one plate pushes beneath the edge of the other in a process called subduction. Because of the compression in these zones, many of the faults there are reverse faults. About 80 per cent of major earthquakes occur in subduction zones encircling the Pacific Ocean. In these areas, the plates under the Pacific Ocean are plunging beneath the plates carrying the continents. The grinding of the colder, brittle ocean plates beneath the continental plates creates huge strains that are released in the world’s largest earthquakes.

The world’s deepest earthquakes occur in subduction zones down to a depth of about 450 miles (700 kilometers). Below that depth, the rock is too warm and soft to break suddenly and cause earthquakes.

Transform faults are places where plates slide past each other horizontally. Strike-slip faults occur there. Earthquakes along transform faults may be large, but not as large or deep as those in subduction zones.

One of the most famous transform faults is the San Andreas Fault. The slippage there is caused by the Pacific Plate moving past the North American Plate. The San Andreas Fault and its associated faults account for most of California’s earthquakes.

Intraplate earthquakes are not as frequent or as large as those along plate boundaries. The largest intraplate earthquakes are about 100 times smaller than the largest interplate earthquakes.

Intraplate earthquakes tend to occur in soft, weak areas of plate interiors. Scientists believe intraplate quakes may be caused by strains put on plate interiors by changes of temperature or pressure in the rock. Or the source of the strain may be a long distance away, at a plate boundary. These strains may produce quakes along normal, reverse, or strike-slip faults.

Studying earthquakes

Recording, measuring, and locating earthquakes

To determine the strength and location of earthquakes, scientists use a recording instrument known as a seismograph. A seismograph is equipped with sensors called seismometers that can detect ground motions caused by seismic waves from both near and distant earthquakes. Some seismometers are capable of detecting ground motion as small as 0.1 nanometer. One nanometer is 1 billionth of a meter or about 39 billionths of an inch. Scientists called seismologists measure seismic ground movements in three directions: (1) up-down, (2) north-south, and (3) east-west. The scientists use a separate sensor to record each direction of movement.

A seismograph produces wavy lines that reflect the size of seismic waves passing beneath it. The record of the wave, called a seismogram, is imprinted on paper, film, or recording tape or is stored and displayed by computers.

Probably the best-known gauge of earthquake intensity is the local Richter magnitude scale, developed in 1935 by United States seismologist Charles F. Richter. This scale, commonly known as the Richter scale, measures the ground motion caused by an earthquake. Every increase of one number in magnitude means the energy release of the quake is about 32 times greater. For example, an earthquake of magnitude 7.0 releases about 32 times as much energy as an earthquake measuring 6.0. An earthquake with a magnitude of less than 2.0 is so slight that usually only a seismometer can detect it. A quake greater than 7.0 may destroy many buildings. The number of earthquakes increases sharply with every decrease in Richter magnitude by one unit. For example, there are 8 times as many quakes with magnitude 4.0 as there are with magnitude 5.0.

Although large earthquakes are customarily reported on the Richter scale, scientists prefer to describe earthquakes greater than 7.0 on the moment magnitude scale. The moment magnitude scale measures more of the ground movements produced by an earthquake. Thus, it describes large earthquakes more accurately than does the Richter scale.

The largest earthquake ever recorded on the moment magnitude scale measured 9.5. It was an interplate earthquake that occurred along the Pacific coast of Chile in South America in 1960. The largest intraplate earthquakes known struck in central Asia and in the Indian Ocean in 1905, 1920, and 1957. These earthquakes had moment magnitudes between about 8.0 and 8.3. The largest intraplate earthquakes in the United States were three quakes that occurred in New Madrid, Missouri, in 1811 and 1812. The earthquakes were so powerful that they changed the course of the Mississippi River. During the largest of them, the ground shook from southern Canada to the Gulf of Mexico and from the Atlantic Coast to the Rocky Mountains. Scientists estimate the earthquakes had moment magnitudes of 7.5.

Scientists locate earthquakes by measuring the time it takes body waves to arrive at seismographs in a minimum of three locations. From these wave arrival times, seismologists can calculate the distance of an earthquake from each seismograph. Once they know an earthquake’s distance from three locations, they can find the quake’s focus at the center of those three locations.

Predicting earthquakes

Scientists can make fairly accurate long-term predictions of where earthquakes will occur. They know, for example, that about 80 percent of the world’s major earthquakes happen along a belt encircling the Pacific Ocean. This belt is sometimes called the Ring of Fire because it has many volcanoes, earthquakes, and other geologic activity.

Scientists are working to make accurate forecasts on when earthquakes will strike. Geologists closely monitor certain fault zones where quakes are expected. Along these fault zones, they can sometimes detect small quakes, the tilting of rock, and other events that might signal a large earthquake is about to occur.

Exploring Earth’s interior

Most of what is known about the internal structure of Earth has come from studies of seismic waves. Such studies have shown that rock density increases from the surface of Earth to its center. Knowledge of rock densities within Earth has helped scientists determine the probable composition of Earth’s interior.

Scientists have found that seismic wave speeds and directions change abruptly at certain depths. From such studies, geologists have concluded that Earth is composed of layers of various densities and substances. These layers consist of the crust, mantle, outer core, and inner core. Shear waves do not travel through the outer core. Because shear waves cannot travel through liquids, scientists believe the outer core is liquid. Scientists believe the inner core is solid because of the movement of compressional waves when they reach the inner core.

Chile quake similar to 2004 Indian Ocean temblor

Residents look at a collapsed building in Concepcion, Chile, Saturday Feb. 27, 2010 after an 8.8-magnitude struck central Chile. The epicenter was 70 miles (115 kilometers) from Concepcion, Chile’s second-largest city. (AP Photo

(AP) — Scientists say the major earthquake that struck off the coast of Chile was a “megathrust” – similar to the 2004 Indian Ocean temblor that spawned a catastrophic tsunami.

Megathrust earthquakes occur in subduction zones where plates of the Earth’s crust grind and dive. Saturday’s jolt occurred when the Nazca plate dove beneath the South American plate, releasing tremendous energy.

The U.S. Geological Survey says 13 temblors of magnitude-7 or larger have hit coastal Chile since 1973.

The latest quake occurred about 140 miles north of the largest earthquake ever recorded. The magnitude-9.5 struck southern Chile in 1960, killing some 1,600 people and generating a tsunami that killed another 200 people in Japan, Hawaii and the Philippines.

The Liquiñe-Ofqui Fault is major geological fault[1] that runs a length of roughly 1000 km in a north-south direction and exhibits current seismicity [2]. It is located in the Chilean northern patagonean Andes.

My Note – as I was looking for information about the earthquake fault zones in Chile and other info about the tsunami earlier today, I also found a few other good things including these which were interesting – cricketdiane

**

magnetic polarity reversal. A change of the earth’s magnetic field to the opposite polarity that has occurred at irregular intervals during geologic time. Polarity reversals can be preserved in sequences of magnetized rocks and compared with standard polarity-change time scales to estimate geologic ages of the rocks. Rocks created along the oceanic spreading ridges commonly preserve this pattern of polarity reversals as they cool, and this pattern can be used to determine the rate of ocean ridge spreading. The reversal patterns recorded in the rocks are termed sea-floor magnetic lineaments.

Quantum measurement precision approaches Heisenberg limit

This illustration shows an adaptive feedback scheme being used to measure an unknown phase difference between the two red arms in the interferometer. A photon (qubit) is sent through the interferometer, and detected by either c1 or c0, depending on which arm it traveled through. Feedback is sent to the processing unit, which controls the phase shifter in one arm so that, when the next photon is sent, the device can more precisely measure the unknown phase in the other arm, and calculate a precise phase difference. Image credit: Hentschel and Sanders.

(PhysOrg.com) — In the classical world, scientists can make measurements with a degree of accuracy that is restricted only by technical limitations. At the fundamental level, however, measurement precision is limited by Heisenberg’s uncertainty principle. But even reaching a precision close to the Heisenberg limit is far beyond existing technology due to source and detector limitations.

Now, using techniques from machine learning, physicists Alexander Hentschel and Barry Sanders from the University of Calgary have recently shown how to generate measurement procedures that can outperform the best previous strategy in achieving highly precise quantum measurements. The new level of precision approaches the Heisenberg limit, which is an important goal of quantum measurement. Such quantum-enhanced measurements are useful in several areas, such as atomic clocks, gravitational wave detection, and measuring the optical properties of materials.

“The precision that any measurement can possibly achieve is limited by the so-called Heisenberg limit, which results from Heisenberg’s uncertainty principle,” Hentschel told PhysOrg.com. “However, classical measurements cannot achieve a precision close to the Heisenberg limit. Only quantum measurements that use quantum correlations can approach the Heisenberg limit. Yet, devising quantum measurement procedures is highly challenging.”

Heisenberg’s uncertainty principle ultimately limits the achievable precision depending on how many quantum resources are used for the measurement. For example, gravitational waves are detected with laser interferometers, whose precision is limited by the number of photons available to the interferometer within the duration of the gravitational wave pulse.

In their study, Hentschel and Sanders used a computer simulation of a two-channel interferometer with a random phase difference between the two arms. Their goal was to estimate the relative phase difference between the two channels. In the simulated system, photons were sent into the interferometer one at a time. Which input port the photon entered was unknown, so that the photon (serving as a qubit) was in a superposition of two states, corresponding to the two channels. When exiting the interferometer, the photon was detected as leaving one of the two output ports, or not detected at all if it was lost. Since photons were fed into the interferometer one at a time, no more than one bit of information could be extracted at once. In this scenario, the achievable precision is limited by the number of photons used for the measurement.

As previous research has shown, the most effective quantum measurement schemes are those that incorporate adaptive feedback. These schemes accumulate information from measurements and then exploit it to maximize the information gain in subsequent measurements. In an interferometer with feedback, a sequence of photons is successively sent through the interferometer in order to measure the unknown phase difference. Detectors at the two output ports measure which way each of the photons exits, and then transmit this information to a processing unit. The processing unit adapts the value of a controllable phase shifter after each photon according to a given policy.

However, devising an optimal policy is difficult, and usually requires guesswork. In their study, Hentschel and Sanders adapted a technique from the field of artificial intelligence. Their algorithm autonomously learns an optimal policy based on trial and error – replacing guesswork by a logical, fully automatic, and programmable procedure.

Specifically, the new method uses a machine learning algorithm called particle swarm optimization (PSO). PSO is a “collective intelligence” optimization strategy inspired by the social behavior of birds flocking or fish schooling to locate feeding sites. In this case, the physicists show that a PSO algorithm can also autonomously learn a policy for adjusting the controllable phase shift.

As Hentschel and Sanders show, after a sequence of input qubits have been sent through the interferometer, the measurement procedure learned by the PSO algorithm delivers a measurement of the unknown phase shift that scales closely to the Heisenberg limit, setting a new precedent for quantum measurement precision. The new high level of precision could have important implications for the gravitational wave detection.

“Einstein’s theory of General Relativity predicts gravitational waves,” Hentschel said. “However, a direct detection of gravitational waves has not been achieved. Gravitational wave detection will open up a new field of astronomy that augments electromagnetic wave and neutrino observations. For example, gravitational wave detectors can spot merging black holes or binary star systems composed of two neutron stars, which are mostly hidden to conventional telescopes.”

Evidence of a new phase in liquid hydrogen

February 25, 2010 By Miranda Marquit

Protium, the most common isotope of hydrogen. Image: Wikipedia.

(PhysOrg.com) — We like to think that we’ve got hydrogen, one of the most basic of elements, figured out. However, hydrogen can still surprise, especially once scientists start probing its properties on the most fundamental levels. “We ran simulations in order to provide a quantitative map of the molecular to atomic transition in liquid hydrogen,” Isaac Tamblyn tells PhysOrg.com. “Some of what we found was surprising, and could change the basic equations of state used in models involving hydrogen.”

Tamblyn is a scientist at Dalhousie University in Halifax, Canada. He worked with Stanimir A. Bonev to simulate the transition in liquid hydrogen, offering evidence for an unreported liquid phase, and noting some interesting structural characteristics of liquid hydrogen. Information on the simulation efforts, as well as results and conclusions, are presented in Physical Review Letters: “Structure and Phase Boundaries of Compressed Liquid Hydrogen.”

“We used first principles molecular dynamics simulations to model the liquid,” Tamblyn explains. “Forces between atoms were obtained using the Schrödinger equation. Velocities of the atoms were then updated, and the system was evolved through time.”

“We ran simulations to determine what would happen under different thermodynamic conditions, like density and temperature, and monitored the stability of molecules as the simulations progressed,” Tamblyn continues. “Our transition line is based on molecular stability. The chances of a molecule surviving are greater in a molecular liquid than in an atomic one, so this is a natural way to describe the transition.”

After running the simulations, Tamblyn and Bonev then had to analyze them. “We discovered an ordering in the liquid that accounts for some of the interesting characteristics of hydrogen, such as the fact that under certain conditions, liquid hydrogen is more dense than the solid. We also found that highly ordered packing explains properties related to dissociation that were previously not well understood.”

The pair found that the simulations suggest criteria for the existence of a first-order phase transition in liquid hydrogen. “The existence of this has been debated,” Tamblyn explains, “and we provide some evidence for its possibility.”

One of the most significant things Tamblyn and Bonev discovered through their simulations, from an astrophysics standpoint, is that equations describing the properties of hydrogen might need to be updated. “This should change the modeling going forward,” Tamblyn insists. “What we found in the liquid suggests what the solid might look like, and that can help determine some of its thermal and electronic properties.”

There is a good chance that planetary models might be changed using the new information on hydrogen structure discovered through these simulations. “Some previous calculations may need to be revised,” Tamblyn predicts. He also says that the simulations hint at some of the potential effects of mixtures involving hydrogen. “We’re especially interested in the implication for hydrogen and helium mixtures.”

Going forward, Tamblyn believes there is room to expand upon the work. “We are looking at the metallization of hydrogen, following the transition into a liquid metal. We are also looking at simulating hydrogen mixtures, especially with helium, to see if our findings hold true.”

Finance

Skyline of Santiago’s Financial District

Chile’s financial sector has grown quickly in recent years, with a banking reform law approved in 1997 that broadened the scope of permissible foreign activity for Chilean banks. The Chilean Government implemented a further liberalization of capital markets in 2001, and there is further pending legislation proposing further liberalization. Over the last ten years, Chileans have enjoyed the introduction of new financial tools such as home equity loans, currency futures and options, factoring, leasing, and debit cards. The introduction of these new products has also been accompanied by an increased use of traditional instruments such as loans and credit cards. Chile’s private pension system, with assets worth roughly $70 billion at the end of 2006, has been an important source of investment capital for the capital market. However, by 2009, it has been reported that $21 billion had been lost from the pension system to the global financial crisis.[62]

Chile maintains one of the best credit ratings (S&P A+) in Latin America.[63] There are three main ways for Chilean firms to raise funds abroad: bank loans, issuance of bonds, and the selling of stocks on U.S. markets through American Depository Receipts (ADRs). Nearly all of the funds raised through these means go to finance domestic Chilean investment. The government is required by law to run a fiscal surplus of at least 1% of GDP. In 2006, the Government of Chile ran a surplus of $11.3 billion, equal to almost 8% of GDP. The Government of Chile continues to pay down its foreign debt, with public debt only 3.9% of GDP at the end of 2006.[6]

Demographics

Chile’s 2002 census reported a population of 15,116,435. Its rate of population growth has been decreasing since 1990, because of a declining birth rate.[64] By 2050 the population is expected to reach approximately 20.2 million.[65] About 85% of the country’s population lives in urban areas, with 40% living in Greater Santiago. The largest agglomerations according to the 2002 census are Greater Santiago with 5.6 million people, Greater Concepción with 861,000 and Greater Valparaíso with 824,000.[66]

Demography

According to the 2002 Census the population of the region was 908,097. With one third of its population living in rural areas, Maule has a greater proportion of rural inhabitants than any other region of Chile.

Economy

Forestry and agriculture, led by wine grape plantations, are the main economic activities. The Maule region is Chile’s leading winemaking region, producing 50% of all the country’s fine export wines, and a number of the largest vineyards are located here. Owing to its high concentration of vineyards, the Curicó valley – which means “black water” in Mapudungun – is considered the core of Chile’s wine industry. Winemaking is a traditional activity, some vineyards dating back to 1830. The increased wine-growing area is matched by the development of the industry’s infrastructure, technology, and equipment.

Electricity, gas and water are the second most important economic activity. The Maule River feeds five hydroelectric power plants, including the Colbún-Machicura complex.

Heritage

The Maule Region has produced a remarkable number of famous men and women, in particular writers and poets but also, statesmen and presidents, scientists and naturalists, churchmen, musicians and folklorists, journalists and historians. Thus, the Maule river – the long and wide artery that runs through the region – has been considered Chile’s literary river par excellence. Many novels and short stories have had the river as their main background or protagonist. Several antologies, author’s dictionaries and essays have given their account of the wealth of culture that the region has generated.

The region can boast many small towns and villages with well-preserved colonial rural architecture both in the religious as well as the civil fields. The Talca and Linares dioceses (the two Roman Catholicdioceses in the Maule region) have several parish churches of particular beauty and architectural and historic value.

Literature

Chileans call their country país de poetas—country of poets.[135][136]Gabriela Mistral was the first Chilean to win a Nobel Prize for Literature (1945). Chile’s most famous poet, however, is Pablo Neruda, who also won the Nobel Prize for Literature (1971) and is world-renowned for his extensive library of works on romance, nature, and politics. His three highly individualistic homes, located in Isla Negra, Santiago and Valparaíso are popular tourist destinations.

I was noticing how strong the aftershocks in Chile and how close together – so, I started doing a bit of the math between the intervals – (its roughly “mathed out” – and not the entire list of aftershocks – but this is what people continue to experience and according to the CNN coverage – these aftershocks can continue for months to come . . . hopefully, people are away from the buildings and houses.)

02-27-10

2 million people have been affected by the Chilean earthquake this morning – according to the President of Chile 3.34 am local time – widespread damage in the Chile capital – aftershocks could be happening for months to come – 7.07 pmET – 214 deaths officially so far –

My Note – after watching the way the tsunami warning was handled generally, several things came to light – one, is that many of the buoys need to be kept repaired and maintained across the whole system; two, that if the tsunami had been any faster and any more than a two – six foot surge, most of the communities surrounding the tsunami warning area would have been screwed; and three, that many people along the coast of California thought the tsunami warning was a hoot and did not appreciate the threat to their own safety that it could have been. Had the tsunami been any one bit bigger, stronger, faster, higher or more compressed as it came in, there would have been no safety to the people along the California coast, partly because they did not take it seriously. The efforts made in Hawaii were surely inconvenient but certainly worth it and if the danger had been any more eminent, faster or of greater magnitude – those efforts would not have been near enough to move that many people out of harm’s way.

The West Coast and Alaska Tsunami Warning Center said water surged 2.2 feet in Santa Monica shortly before 12:30 p.m. PST and less in other areas, including 1.4 feet in San Diego and 1.5 feet in Santa Barbara. Authorities reported scattered unusual tidal surges in San Diego and Ventura north of Los Angeles.

The California Emergency Management Agency has received reports of varying turbulence up and down the coast, but nothing significant yet, said spokesman Jordan Scott.

“It’s a nonevent,” said Maurice Luque, spokesman for the San Diego Fire-Rescue Department.

At San Diego’s La Jolla Shores, the tide receded sharply after a small increase in wave heights, disappointing curious surfers and strollers who expected more. Lifeguards had warned swimmers about the tsunami but didn’t order them to leave. All city beaches stayed open.

David Klein, a San Diego chiropractor, set up a tripod on a bench and filmed himself riding the paltry waves amid intermittent rain. When five or six small waves rolled in, he was convinced he had ridden a tsunami.

The Coast Guard recommended that people in San Diego avoid going near beaches or other low-lying coastal areas, especially jetties and rocky areas. It said large waves can quickly and unexpectedly sweep a person from those areas, easily overtaking even the strongest swimmers.

Boaters and swimmers largely stayed away, but crowds were probably sparse because it rained after several days of sunny weather, said Jetta Disco, a Coast Guard spokeswoman in San Diego.

Coastal communities continued to remain on alert since dangerous waves are still possible hours after the initial waves.

Lt. John Eberhart of San Diego Lifeguard Services said there were unusual tidal surges in Mission Bay and La Jolla Cove, two popular tourist spots, but no reports of injuries or damage.

Ventura Fire Battalion Chief Matt Brock said there was a 3-foot tidal surge in the harbor that receded, causing a dock to become unmoored. There was a 15-foot boat on the dock, but it has been recovered with no damage, he said.

In Northern California, the San Mateo County Sheriff’s Office closed beaches in Pacifica and Half Moon Bay.

California was under a tsunami advisory issued for the entire West Coast, but that didn’t deter surfers competing in a qualifying match of a Professional Longboards Association contest at San Diego’s Ocean Beach.

“We’re just trying to stay on schedule, that’s the biggest thing,” said Jeff Stoner, the association’s executive director, as organizers monitored the tsunami’s progress.

All but five of 72 contestants showed up Saturday, Stoner said. One from Hawaii dropped out to catch a flight home, hoping to join family before the first waves hit the islands.

The tsunami was a hot topic of conversation at coastal coffee shops, though some surfers hadn’t heard about the quake. Their big complaint was choppy waves that measured little more than two feet.

“You could definitely ask for better day,” said Josh Rapozo, 27, of Laguna Niguel, after competing in a qualifying round.

Devastating tsunamis are rare in California. Since 1812, 14 tsunamis with waves higher than 3 feet have been observed along the California coast, but only six caused destruction.

The deadliest occurred in 1964 when a magnitude-9.2 quake in Alaska spawned tsunami waves that killed 12 people in Northern California.

Map Disclaimer: These maps were prepared to assist cities and counties in identifying their tsunami hazard. They are intended for local jurisdictional, coastal evacuation planning uses only. These maps are not a legal documents and do not meet disclosure requirements for real estate transactions nor for any other regulatory purpose. The California Emergency Management Agency (CalEMA), the University of Southern California (USC), and the California Geological Survey (CGS) make no representation or warranties regarding the accuracy of this inundation map nor the data from which the map was derived. Neither the State of California nor USC shall be liable under any circumstances for any direct, indirect, special, incidental or consequential damages with respect to any claim by any user or any third party on account of or arising from the use of this map.

RESTON, Va., Feb. 24 (UPI) — The U.S. Geological Survey says every ice shelf in the southern section of the Antarctic Peninsula is retreating because of climate change.

The USGS says its report is the first to document that every ice front in that area has been retreating overall from 1947 to 2009, with the most dramatic changes occurring since 1990.

The retreat, scientists said, could result in sea-level rise if warming continues, threatening coastal communities and low-lying islands worldwide.

The USGS previously documented the majority of ice fronts on the entire peninsula have also retreated during the late 20th century and into the early 21st century.

Officials said the ice shelves are attached to the continent, holding in place the Antarctic ice sheets that covers about 98 percent of the Antarctic continent. As the ice shelves break off, it becomes easier for outlet glaciers and ice streams from the ice sheet to flow into the sea. That transition of ice from land to the ocean is what raises the sea level.

“This research is part of a larger ongoing USGS project that is for the first time studying the entire Antarctic coastline in detail, and this is important because the Antarctic ice sheet contains 91 percent of Earth’s glacier ice,” USGS scientist Jane Ferrigno said.

“The loss of ice shelves is evidence of the effects of global warming,” she added. “We need to be alert and continually understand and observe how our climate system is changing.”

My Note – According to the article above, there is melting of the great ice sheets and global climate change that I’ve kept wondering whether would increase the amount of weight bearing down on the sea floors as our sea levels are rising. These are massive systems and way past the tipping point already. Oh well, that’s what comes of spending the last forty years telling people that everything is fine the way it is without fixing any of it that’s broken. – cricketdiane

***

U.S. scientists study Haitian earthquake

Published: Feb. 24, 2010 at 1:34 PM

SEATTLE, Feb. 24 (UPI) — A five-person U.S. team evaluating the magnitude-7 earthquake that struck Haiti Jan. 12 says much of the massive loss of life might have been prevented.

The team, led by University of Washington structural engineering.

Professor Marc Eberhard, said its main conclusion was that much of the loss of life could have been prevented by using earthquake-resistant designs and construction, as well as improved quality control in concrete and masonry work. The researchers recommended simple and cost-effective earthquake engineering be emphasized in Haiti’s rebuilding effort.

“A lot of the damaged structures will have to be destroyed,” Eberhard said. “It’s not just 100 buildings or 1,000 buildings. It’s a huge number of buildings, which I can’t even estimate.

“Usually when I go to earthquakes I find that the amount of damage is less than what appears on the television,” Eberhard said. “In this case it was much more.”

One of the worst things about the caste system that was established in the United States over the years since Nixon and Reagan, is that when there were emergency management planning and drills whether in small towns or large cities, often the ones who would not be the decision-makers during a crisis or disaster were sent to the meetings and emergency preparedness drills since “bigwigs” can’t be bothered with such things. Once a crisis occurs, the secretary, assistant, office manager, dispatcher, vice president, vice chairman, assistants and staff to the top people generally are not available and the one left to make decisions for all of us affected by the disaster would end up being the asshole who didn’t go to any of the planning meetings, nor to any of the drills because they couldn’t be bothered with it being too important for such things. Anyway, once that costs lives doing it that way, I would think the people who have the top positions of authority in the US locally and regionally, would consider learning more about acting in an organized and coordinated manner along with how to accomplish that during high stress, dangerous and life-threatening extreme events. It would be nice to see that happen in America. But, if today had been the day when this disaster in Chile had happened in the United States, the outcome would have been an absolute nightmare that defies description and anybody who doesn’t recognize that at this point isn’t paying attention. The best idea would be to fix it before we get there.

– cricketdiane

***

And I would love to know why the entire slabs in the concrete slab construction buildings (at least in some of them) did not crack into a million pieces despite the underneath columns being torn from the slab above. However they built those buildings – it is worth building some more like them. The comparison between these and the many recent concrete slab buildings which have been nothing but a pile of pancaked floors in rubble is phenomenally impressive. It looks like a lot of things in earthquake resistant building techniques worked and some used on roads and bridges didn’t. And, although there were buildings of multi-stories that were damaged, the majority of compartments where people would be – were intact despite the violence of the earthquake and damage to the building. – my note, (cd)

Tsunami Messages for All Regions (Past 10 Days)

Click on the map or table below for more information.

**

There’s also an issue relating to maintenance of the sensor network: Last year, Public Employees for Environmental Responsibility issued a report pointing to what it said were “gaping holes” in the tsunami warning system. NOAA’s records indicate that 10 out of its 39 deep-ocean pressure monitoring stations, also known as DART buoys, were failing. Still more deep-ocean sensors operated by other countries are on the blink.

Officials at NOAA acknowledge that keeping the stations in operation can be a problem, and they’ve asked mariners to help out by staying well away from the buoys and reporting any damaged or drifting buoys to the U.S. Coast Guard.

This report is an updated version of a Cosmic Log posting that was first published in September 2009.

The 6.3-magnitude earthquake struck about 15 miles (20 km) northwest of Salta, the capital city of the country’s Salta Province. It struck around 12.45 p.m. local time (15.45 GMT) at a depth of 23.7 miles (38.2 km).

The Buenos Aires Herald reported that the earthquake killed an eight-year-old boy when a wall collapsed in Salta city, while several others were injured.

Even though media reports initially said the earthquake was an aftershock from an 8.8-magnitude earthquake that struck Chile earlier on Saturday, a seismologist at the U.S. Geological Survey denied that.

The seismologist said the earthquake struck too far away from Chile’s epicenter to be an aftershock. However, he said, the earthquake in Argentina may have been triggered by the earthquake in Chile. “We don’t know yet, but its not an aftershock.”

The seismologist explained that aftershocks are not the same as an earthquake-triggered earthquake.

My Note – this thing looks like its still moving – and most of the aftershocks are very large and close together – structures that may have made it through the original earthquake may not make it after the continuing structural fatigues from aftershocks and in the pictures, it looks like people are going back into structures to recover mattresses and household goods – that’s gotta stop –

There may be other pictures from Argentina and surrounding places where they have had some earthquakes at this same time and / or damages from the Chile 8.8 earthquake this morning. I should look around a bit more . . .

There would have been hundreds of thousands dead if it had not been for Chile putting in place, earthquake resistant building codes. I still do not understand why so many roadways, bridges and support columns in buildings gave way as if they had no integrity at the point of connection to their primary structures. There are places with nothing but rubble, but many, many buildings in Chile that have been shown on the news have compartments where people’s living spaces stayed intact, even though portions of the buildings were damaged. That is remarkable and has definitely resulted in lower numbers of casualties than what would have occurred.

In California and other earthquake prone areas, I wish they would bring every single building and residence up to a code standard of earthquake resistance, including the use of everything the recent earthquakes in Haiti and Chile, L’Aquila and Sichuan have taught us. There are too many structures which still need to be retrofitted for earthquake resistant measures. It still seems that we desperately need a masonry building material / cement / mortar recipe that works extremely better during earthquakes, tsunamis, tornadoes, hurricanes, under extreme stresses / fatigue and especially during extreme events. It continues to be that the mortar is the weak point in the structures with the resulting catastrophic failures of those building materials during extreme events in particular.

Thank God for the leaders, builders, engineers and construction specialists in Chile that have made sure so many of these buildings and structures did have earthquake resistant building measures used. Where those measures did not fully protect, they simply did make the loss of life and damages to human life far less than it could have been. It is truly amazing to see the pictures with areas where people were living in buildings survive the earthquake intact. Truly amazing. We need to do that everywhere as part of the process of building, rebuilding and as a policy, to retrofit every structure to be better able to withstand extreme events, particularly earthquakes – especially where people could be inside those structures.

– cricketdiane

**

President Obama is speaking now – 1.47 pm (02-27-10)

**

Tsunami Event – February 27, 2010 ChileMain Event Page

The Chile tsunami was generated by a Mw 8.8 earthquake (35.846°S, 72.719°W ), at 06:34 UTC, 115 km (60 miles) NNE of Concepcion, Chile (according to the USGS). In approximately 3 hours, the tsunami was first recorded at DART® buoy 32412. Forecast results shown below were created with the NOAA forecast method using MOST model with the tsunami source inferred from DART® data.

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The tsunami waves first arrived at Valparaiso, Chile (approximately 330 km northeast from earthquake epicenter ) earlier than other tide gages, at 0708UTC, about 34 minutes after the earthquake.

The graphics to the left display forecast results, showing qualitative and quantitative information about the tsunami, including tsunami wave interaction with ocean floor bathymetric features, and neighboring coastlines. Tsunami model amplitude information is shown color-coded according the scale bar.

A tsunami is a series of ocean waves generated by sudden displacements in the sea floor, landslides, or volcanic activity. In the deep ocean, the tsunami wave may only be a few inches high. The tsunami wave may come gently ashore or may increase in height to become a fast moving wall of turbulent water several meters high.

Although a tsunami cannot be prevented, the impact of a tsunami can be mitigated through community preparedness, timely warnings, and effective response.

NOAA has primary responsibility for providing tsunami warnings to the Nation, and a leadership role in tsunami observations and research.

Tectonic Summary

This earthquake occurred at the boundary between the Nazca and South American tectonic plates. The two plates are converging at a rate of 80 mm per year. The earthquake occurred as thrust-faulting on the interface between the two plates, with the Nazca plate moving down and landward below the South American plate.

Coastal Chile has a history of very large earthquakes. Since 1973, there have been 13 events of magnitude 7.0 or greater. The February 27 shock originated about 230 km north of the source region of the magnitude 9.5 earthquake of May, 1960 – the largest earthquake worldwide in the last 200 years or more. This giant earthquake spawned a tsunami that engulfed the Pacific Ocean. An estimated 1600 lives were lost to the 1960 earthquake and tsunami in Chile, and the 1960 tsunami took another 200 lives among Japan, Hawaii, and the Philippines. Approximately 870 km to the north of the February 27 earthquake is the source region of the magnitude 8.5 earthquake of November, 1922. This great quake significantly impacted central Chile, killing several hundred people and causing severe property damage. The 1922 quake generated a 9-meter local tsunami that inundated the Chile coast near the town of Coquimbo; the tsunami also crossed the Pacific, washing away boats in Hilo harbor, Hawaii. The magnitude 8.8 earthquake of February 27, 2010 ruptured the portion of the South American subduction zone separating these two massive historical earthquakes.

A large vigorous aftershock sequence can be expected from this earthquake.

Coastal Chile has a history of deadly earthquakes, according to the USGS. Since 1973, there have been 13 quakes of magnitude 7.0 or higher.

Saturday’s epicenter was just a few miles north of the largest earthquake recorded in the world, a magnitude 9.5 quake in May 1960 that killed 1,655 and unleashed a tsunami that crossed the Pacific.

The earthquake off the west coast of South America caused a tsunami that reached the Hawaiian Islands in about 15 hours. This tsunami caused little damage elsewhere in the islands, but the Hilo Bay area was hard hit. Sixty-one people lost their lives and about 540 homes and businesses were destroyed or severely damaged. The wave heights in Hilo Bay reached 35 feet compared to only 3-17 feet elsewhere.

PAGER – M 8.8 – OFFSHORE MAULE, CHILE

Alert Version: 6Saturday, February 27th, 2010 at 06:34:14 UTCLocation: 35.8° S, 72.7° WDepth: 35kmEvent Id: US2010TFANCreated: 9 hours, 10 minutes after earthquake.
Overall, the population in this region resides in structures that are vulnerable to earthquake shaking, though some resistant structures exist. On May 22, 1960 (UTC), a magnitude 9.5 earthquake 273 km South of this one struck Valdivia, Chile, with estimated population exposures of 230,000 at intensity VIII and 216,000 at intensity IX , resulting in a reported 3263 deaths from the earthquake and tsunami. Recent earthquakes in this area have caused tsunamis, landslides, and liquefaction that may have contributed to losses.

Downloads

PAGER results are generally available on the Internet within 30 minutes of the earthquake’s occurrence. However, information on the extent of shaking will be uncertain in the minutes and hours following and earthquake and typically improves as additional sensor data and reported intensities are acquired and incorporated into models of the earthquake’s source. Users of PAGER estimates should account for uncertainty and always seek the most current PAGER release for any earthquake.

For inquiries about relatives living and who have citizenship in Chile, please try to keep calling, monitor their social networking profiles or contact other family members who live nearby. Telephone, Internet and other communication lines are often disrupted in times of disaster. People trying to locate U.S. citizens living or traveling in Chile should contact the U.S. Department of State, Office of Overseas Citizens Services, at 1-888-407-4747 or 202-647-5225.

Update 11:15am
The American Red Cross has pledged an initial $50,000 from the International Response Fund to assist communities impacted by today’s earthquake in Chile. We are prepared to take further action as local responders assess the situation.

******

We are waking up to news of a massive earthquake in Chile.

We are working with the International Federation of Red Cross / Red Crescent to determine if and how the American Red Cross is responding.

To ask for or provide information about US citizens in Chile, contact the US State Dept at 1-888-407-4747.

Earth scientists began recording earthquakes about 1880, but it was not until the 1940’s that instruments were installed in buildings to measure their response to earthquakes. The number of instruments installed in strucures increased in the 1950’s and 1960’s. The first abundant data on the response of structures came from the devastating 1971 San Fernando, California, earthquake, which yielded several dozen records. These records were primitive by today’s standards. The first records from instruments sophisticated enough to measure twisting of a building were obtained during the 1979 Imperial Valley, California, earthquake.

Today there are instruments installed in hospitals, bridges, dams, aqueducts, and other structures throughout the earthquake-prone areas of the United States, including Illinois, South Carolina, New York, Tennessee, Idaho, California, Washington, Alaska, and Hawaii. Both the California Division of Mines and Geology (CDMG) and the USGS operate instruments in California. The USGS also operates instruments in the other seismically active regions of the nation.

(Click on image for a full size version – 128K)
Earthquakes are a widespread hazard in the United States. Colors show magnitudes of historical earthquakes: red, 7 or greater; orange, 5.5 to 7; yellow, 4.5 to 5.5. The U.S. Geological Survey operates instruments in many structures in the seismically active areas shown. These instruments measure how structures respond to earthquake shaking.
Designing and building large structures is always a challenge, and that challenge is compounded when they are built in earthquake-prone areas. More than 60 deaths and about $ 6 billion in property damage resulted from the Loma Prieta earthquake. As earth scientists learn more about ground motion during earthquakes and structural engineers use this information to design stronger buildings, such loss of life and property can be reduced.

To design structures that can withstand earthquakes, engineers must understand the stresses caused by shaking. To this end, scientists and engineers place instruments in structures and nearby on the ground to measure how the structures respond during an earthquake to the motion of the ground beneath. Every time a strong earthquake occurs, the new information gathered enables engineers to refine and improve structural designs and building codes. In 1984 the magnitude 6.2 Morgan Hill, California, earthquake shook the West Valley College campus, 20 miles away. Instruments in the college gymnasium showed that its roof was so flexible that in a stronger or closer earthquake the building might be severely damaged, threatening the safety of occupants. At that time, these flexible roof designs were permitted by the Uniform Building Code (a set of standards used in many states). Many industrial facilities nationwide were built with such roofs.

(Click on image for a full size version – 82K)
Seismic records (upper right) obtained during the 1984 Morgan Hill, California, earthquake led to an improvement in the Uniform Building Code (a set of standards used in many states). The center of the gym roof shook sideways three to four times as much as the edges. The Code has since been revised to reduce the flexibility of such large-span roof systems and thereby improve their seismic resistance.
Building codes provide the first line of defense against future earthquake damage and help to ensure public safety. Records of building response to earthquakes, especially those from structures that failed or were damaged, have led to many revisions and improvements in building codes. In 1991, as a direct result of what was learned about the West Valley College gymnasium roof, the Uniform Building Code was revised. It now recommends that such roofs be made less flexible and therefore better able to withstand large nearby earthquakes.

Earth scientists began recording earthquakes about 1880, but it was not until the 1940’s that instruments were installed in buildings to measure their response to earthquakes. The number of instruments installed in strucures increased in the 1950’s and 1960’s. The first abundant data on the response of structures came from the devastating 1971 San Fernando, California, earthquake, which yielded several dozen records. These records were primitive by today’s standards. The first records from instruments sophisticated enough to measure twisting of a building were obtained during the 1979 Imperial Valley, California, earthquake.

Today there are instruments installed in hospitals, bridges, dams, aqueducts, and other structures throughout the earthquake-prone areas of the United States, including Illinois, South Carolina, New York, Tennessee, Idaho, California, Washington, Alaska, and Hawaii. Both the California Division of Mines and Geology (CDMG) and the USGS operate instruments in California. The USGS also operates instruments in the other seismically active regions of the nation.

(Click on images for full size versions – 192K, 238K, 98K, 114K)
USGS scientists have installed instruments in a variety of structures across the United States to monitor their behavior during earthquakes. Examples shown include a dam, a bridge supporting a large aqueduct, a highway overpass, and a Veterans hospital.
The majority of deaths and injuries from earthquakes are caused by the damage or collapse of buildings and other structures. These losses can be reduced through documenting and understanding how structures respond to earthquakes. Gaining such knowledge requires a long-term commitment because large devastating earthquakes occur at irregular and often long intervals. Recording instruments must be in place and waiting, ready to capture the response to the next temblor whenever it occurs. The new information acquired by these instruments can then be used to better design earthquake-resistant structures. In this way, earth scientists and engineers help reduce loss of life and property in future earthquakes.

Mehmet Celebi, Robert A. Page, and Linda Seekins

COOPERATING AGENCIES, COMPANIES, AND INSTITUTIONS
California Department of Transportation
California Division of Mines and Geology
City of Los Angeles
General Services Administration
Metropolitan Water District of Southern California
Oregon Department of Highways
U.S. Army Corps of Engineers
U.S. Department of Energy
U.S. Department of Veterans Affairs
Washington Department of Highways
Washington Department of Natural Resources
Private building owners